var gulp = require('gulp');
var sass = require('gulp-sass');
var uglify = require('gulp-uglify');
var rename = require('gulp-rename');
var autoprefixer = require('gulp-autoprefixer');

function server(){
    gulp.watch('src/sass/*.scss',mySass) 
}
function mySass() {
    return gulp.src('src/sass/*.scss')
    .pipe(sass())
    .pipe(autoprefixer("last 2 versions", " > 5 % ", "IE 10", "IE 9"))
    .pipe(gulp.dest("dist/css"));
  }
  gulp.task('default',gulp.series(mySass,server))  // 不用单引号！！！